For an encore, he opened a locked door without a key. When anyone else touched the handle, it remained locked.

Unlike other magicians, Kramer willingly explained the secret to the trick, which is so simple a dog could perform it: In the flesh between his left thumb and forefinger, he has inserted a tiny glass bead containing an NFC chip.

There's no point trying to teach your pedigree pooch this trick: It probably already knows how it's done. Microchipping of valuable pets and livestock is increasingly common, and is already mandated in some countries. It will become compulsory for dogs in England and Scotland from April, and is already required in other parts of the U.K.

Kramer's company, Digiwell, can microchip you too, right here at the Cebit trade show in Hanover, Germany.

The company sells two types of implant: the newer xNT, which operates at 13.56MHz, and the 125kHz xEM, compatible with older RFID access control systems.

As with other NFC chips, you can use a suitably equiped mobile phone to read from or write to the xNT, which is how Kramer's business card trick works.

It will cost you €69 (US$77) including the special syringe to insert it and a few bits and bobs to keep everything sterile while you do it. It's possible to do it yourself, but Digiwell recommends you have it done by someone qualified -- a category that includes tattoists and veterinarians.

You can get chipped for free at Cebit if you'll submit to the procedure on stage during what Kramer refers to as "happy hours." They start at 10 a.m. and 4 p.m. every day till the show closes on Friday.

Cebit received over 200,000 visitors last year, but only 10 or 15 of those are likely to submit to the chipping process, Kramer said.

"Thirty would be a huge success," at an enterprise IT trade show like Cebit, he said, although Digiwell typically implants that many chips at much smaller events dedicated to "biohacking," a field at the intersection of citizen science and body modification.

The key question, of course, is does having a chip implant hurt?

This reporter wasn't ready to find out, but Kramer said it's like pinching yourself between the thumb and forefinger: a sensation of discomfort, rather than pain.

"We have some people who think it really hurts, and others who say, 'Oh, did you already do it?' Everyone reacts differently," he said.

Even if there's no pain, what might you gain? Kramer uses his chip implant to carry his business card and to open the front door of his house, which is fitted with a special NFC lock. Other applications being tested include authorizing bitcoin payments and checking in for flights, he said.

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